US1397067A - Crown-tooth - Google Patents

Description

J. L. WILLIAMS.

CROWN TOOTH.

APPLICATION FILED JAN.29,1920- 1,397,067. A Patented Nov. 15,1921.

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JAMES LEON WILLIAMS, OF NEW YGRK, N. Y., ASSIGNOR TO THE DENTISTS SUPPLY COIVIPANY. A CORPORATION OF NEW YORK.

CRO NN-TOOTH.

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Application filed January 29, 1920.

To all "whom it may concern.

Be it known that I, Jiuuns LEON VVILLIAMs, a citizen of the United States, and resident of New York city, county of New York, and State of New York, have invented an Improvement in Crown-Teeth, of which the following is a specification.

Heretofore, the construction of crown teeth, employing pins for attachment to roots, have not been proportioned or shaped properly to give the greatest possible strength, and this also applies to the pin, as to its shape on that part which enters the hole or recess in the porcelain tooth.

At the neck, the greatest diameter of the anterior teeth (for which the great majority of porcelain crowns are made) is bucco-lingually, but the greatest diameter of the incisal half of the crown is in the opposite di rection, that is to say, mesio-distally; and by reason of this fact, objection arises to the old style of pin (which, in the part entering the crown, is of the same diameter throughout), because the hole which receives the pin, if continued a sufficient depth into the porcelain to make the hold secure, often and especially in short teeth, nearly cuts through the lingual surface of the porcelain tooth and thereby greatly weakening it. It is also often found necessary in order to get proper occlusion, to grind the lingual surface of the porcelain crown and in doing this the pin hole is sometimes exposed through the tooth wall. Thus, by the removal of porcelain to the pin hole and by the exposure of the cement which fastens the pin to the crown and the disintegrating action of the saliva, there results a double weakening of crown and attachment.

The object of my invention is to provide a construction of crown tooth and pin structure adapted thereto which will overcome the objections above pointed out as existing in'the structures at present in common use.

In my invention, that portion of the pin entering the porcelain is shaped to correspond with the shape of the crown, and like the crown, it is thin bucco-lingually and wide mesio-distally at the lower end. While containing even more metal than the round pin yet by being flattened at its lower extremity it can be made to pass deeper into the porcelain crown; and on the principles of leverage, a little additional length of J pin adds greatly to the security of the at- Specification of Letters Patent.

Patented Nov, 15,1921.

Serial No. 354,980;

tachment. *While firmer attachment is thus secured, the substance of the porcelain is at the same time conserved so that considerable grinding on the lingual surface of the tooth can bedone without materially weakening it.

My invention further embodies a crown tooth with a large flattened recess about the pin hole and with undercut side walls and in which a wide annular shoulder on the pin tits and is securely cemented therein. The deep hole into which the pin extends is also undercut and likewise insures a stron attachment. O A. further feature of improvement resides in making the crown at the buccal side with a full height, but on the lingual side cutting away the neck of the crown sufliciently to give space for the metal coping and thereby making it easy for thedentist to fit the crown to the root, since the only actual fitting of the tooth itself will be at the buccal edge.

I also direct attention to the fact that this same crown may be used on vulcanite or gold plates or on fixed or removable bridges, these uses only requiring the portion of the pin above the shoulder to be formed or shaped to suit the particular character of work to be made, all of which will be more clearly understood from the description hereinafter.

My invention also consists of improve me'nts hereinafter described whereby the above objects and results are attained, said improvements comprising certain organization and combination of parts which are fully described hereinafter and more particularly defined in the claims.

Referring to the drawing: Figure l is a vertical section, bueco-lingually, of a crown embodying my invention fitted to a natural root Fig. Qis a vertical section, mesio-distally, of the crown and pin embodying my invention before being fitted to the tooth root; Fig. 3 is a plan view, looking downward upon my improved crown (with the pin removed); and Fig. l is a-perspective view of my improved pin before being applied to the tooth crown.

'2 is the tooth root, 3 is the porcelain crown, 4: is the attaching pin, and 5 is the metal coping between the crown and root.

The pin 4': comprises the long tapering part 16 which enters the hole 13 in the natural root, the short pin portion 18, which enters the hole in the porcelain crown, and the annular collar or shoulder 14. at the juncture of the parts 16 and 18.

The short pin portion 18 is of somewhat larger diameter at its end adjacent the collar 14. than the root prong or pin part 16 and the portion is, furthermore, flattened at its end 20 so that at this part it is thin and wide, and when. fitted to the crown, the wide diameter extends mesio-distally of the crown. The portion 18 will be tapering in the bucco-lingual direction (Fig. 1), but fantail in shape in the mesio-distal direction, the greatest width being at or near the end which is received in the bottom part of the hole in the crown, (Fig. 2). The pin part 16 is provided with several annular grooves 17, the pin part 18 with annular grooves 19, and the collar with an annular groove 15, the several grooves being intended to receive the cement and more positively retain the pin structure in position.

The crown 3 is shaped to correspond to the natural shape of the exposed natural tooth beyond the neck, except that in my improved crown, the neck portion to the rear of the buccal edge 10 is cut down to the level 11 in Fig. 1, to give space rearward to the lingual surface for the metal coping 5 which fills the space between the crown and root, as shown in Fig. 1. The hole 6 in the crown, at the point 7, where the pin enters, is oval in outline (Fig. 3) to admit the flattened and widened end 20 of the pin portion 18. Both the recess 8, which receives the shoulder 141 of the pin, and the deeper part of the hole 6, are undercut. This undercut insures very secure locking of pin to crown, when the crown is cemented at 5 to the pin. This undercut for the recess 8 is formed by the beveled side walls 9; and for the hole 6 the undercut is in the mesio-distal direction, as shown in Fig. 2.

This crown is designed to be used with a metal cap or a cast metal coping, as above stated, and it is, therefore, necessary that the lingual part of the neck of the tooth be cut away, as at 11, to give space for the metal coping 5; and this makes the fitting of the crown very easy for the dentist, as the only fitting ever required will be at the thin buccal edge 10. When this fitting of the buccal edge has been done, a suitable piece of warmed wax is passed over the root end 16 of the pin, the pin in serted in the crown and the whole pressed to place over the end of the root. The surplus wax is then trimmed away, the crown removed and the pin with wax in vested for casting. The casting may be made directly to the end of the root or to a metal cap which has been previously fitted to the end of the root, as will be readily understood by dentists.

While I have specially illustrated my improved crown and engaging pin for applipresent invention.

cation to the natural root, the same porcelain tooth may be used 011 vulcanite or gold plates or on fixed or removable bridges, as may be required. For all of these uses, the only necessary change is in the form of the upper end of the pin for the attachmentto the plates or bridges. For gold plate and bridge work, it is merely required that a portion of the root end of the pin be cut off. and then the pin with tooth in position may be fitted to place. The tooth is then removed and the pin soldered or otherwise made fast to the plate or bridge, after which, the crown may be cemented to the pin.

in all uses of this tooth, the porcelain is never subjected to the risks of breakage by the heat of the soldering or casting processes The porcelain is always removed, after the necessary fitting, until the casting or soldering process is completed, after which. the crown is attached-to its pin by cementing.

In using this tooth for vulcanite plates, a slightly different form for the pin above the shoulder 14 is required, this being to provide a suitable head or anchoring part, to become embedded in the vulcanite very mu h as headed pins of soldered pin teeth are embedded for attaching teeth of that character to vulcanite plates, but this particular feature need not be described in detail, as it forms no specific part of the I Reference is made to such use, however, as showing the adaptability of my improved crown and pin structure directly attached thereto for all possible required uses in practice.

Among the more particular advantages resulting from this form of tooth may be mentioned the following: That as a tooth for plates, crown and bridges, it is strong and secure in its attachment, this strength and security of attachment being attained by the mechanically correct shape of the pin in relation to the crown, the dovetail form of the crown end 20 of the pin and the corresponding undercutting of the pin cavity G in the crown; the great simplicity and ease of adjustment due to the fact that the only fitting required is on the thin buccal edge which is easily ground, the back being cut away to receive the wax for the. casting process; its adaptability for vulcanite plate work and as such is far stronger than any tooth with baked-in or soldered pins can be made; and as a tooth for plate work, the tooth has the advantage of having the same shape and conformation as the natural tooth, including the lingual surface, by reason of which the patient, in speech may avoid causes which produce lisping or thickness of speech, and secure general comfort in the use of the tongue, and in ease .of cleanliness.

In case of breakage from any cause, my improved crown may be easily replaced in a few minutes by merely clearing away the remains of the broken tooth and cementing a new one in its place, and this applies to all of the special uses of the tooth, whether for natural roots, metal plate and bridge work, or for vulcanite work.

It will now be apparent that I have devised a novel and useful construction which embodies the features of advantage enumerated as desirable, and while .I have in the present instance shown and described the preferred embodiment thereof which has been found in practice to give satisfactory and reliable results, it is to be understood that I do not restrict myself to the details,

as the same are susceptible of modificationin various particulars without departing from the spirit or scope of the invention.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is:

l. A crown tooth having the hole in its body made wider at its inner end in a direction mesio-distally of the tooth than at its outer or open end and at said outer end having the hole wider in a mesio-distally direction than in a bucco-lingual direction, and further having the hole of an oval shape in cross section at its outer end and gradually reduced in bucco-lingual direction and widened in the mesio-distal direction to provide a narrow and elongated cross section at the inner end.

2. The invention according to claim 1, having the open end of the hole surrounded with a shallow recess of greater diameter than the hole and having abrupt undercut side walls.

3. The invention according to claim 1, combined with a pin cemented in the hole and having its lower end flattened and of a width greater than its upper portion, said lower portion being of a less width than the smallest diameter of the hole mesio-distally of the tooth, whereby the pin is securely attached to the crown and the latter is firmly held against rotation upon the pin.

t. A crown tooth having the hole in its body made wider at its lower part mesiodistally of the tooth than at its upper part,

combined with a pin having an annular collar fitting the upper part of the tooth and an extended shank of smaller diameter flat tened at its end and fitting into the hole in the tooth, said pin secured to the tooth by cement.

5. A crown tooth having a hole extending into its body and opening through the top thereof, said hole at the bottom having a width mesio-distally greatly exceedingthe width bucco-lingually to provide a flattened recess and further having a shallow recess surrounding its open end, said recess having undercut side walls.

6. The invention of claim. 5, combined with an anchor pin having its lower part flattened and fitting the hole in the tooth and having an annular collar fitting the shallow undercut recess, said pin and its collar cemented in place in the tooth.

7. A crown tooth having a hole extending into its bottom and opening through the top thereof, said hole at the bottom having a width mesio-distally greatly exceeding the width bucco-lingually and gradually flaring outwardly into an oval cross section in which the opening is greater mesio-distally than bucco-lingually and in which further the hole at the bottom bucco-lingually is greatly less than the width of the hole at the open end bucco-lingually considered, in combination with an anchor pin having its end of flattened shape and its body approximating a circular shape adjacent to the outer end of, the hole and said pin secured in position within the hole by cement.

8. An anchor pin for a crown tooth, comprising a pin body having an annular collar, an extended part to one side of the collar having a flattened end, and an extended portion to the other side of the collar constructed for attachment to a part to which the crown tooth is to be secured by the pin.

9. An anchor pin comprising a long tapered pin body having an annular shoulder provided with a peripheral groove, and further having an anchoring portion beyond the collar made flattened to provide a fantail structure.

In testimony of which invention, I here unto set my hand.

JAMES LEON WVILLIAMS.

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